Hope I got this right - really foggy. from https://blogs.jwatch.org/hiv-id-obs...questions-from-id-in-primary-care/2017/10/29/ How long does the Lyme serology stay positive after treatment? Although Lyme serologies gradually decline in most patients, they can in individual patients persist for years, making follow-up serologies as a “test of cure” a particularly confusing practice — so let’s stop doing it! Importantly, this applies to both IgM and IgG antibody responses, which makes IgM antibodies an unreliable marker of recent infection unless they are correlated with recent-onset symptoms and exposure. Because there are no predictors of who will and will not have persistent Lyme antibodies, most of the time the diagnosis of reinfection relies heavily on clinical presentation. I hope someone out there is working on a reliable PCR or antigen test for Lyme — we really need it!